In this simple example, we don't have any display-specific properties
or actions just yet. For now, our controller's model property acts as a
pass-through (or "proxy") for the model properties. (Remember that
a controller gets the model it represents from its route handler.)

Let's say we wanted to add a feature that would allow the user to
toggle the display of the body section. To implement this, we would
first modify our template to show the body only if the value of a
new isExpanded property is true.